Section 722 BS7671:2018 Amendment 1 2020 : Electric Vehicle Charging Installations
A brief overview
722.1 Scope: Section 722 does not apply to electric vehicle charging points that employ inductive charging or to mobility scooter and similar chargers for vehicles of 10 A or less.
722.311: Load curtailment, reduction or disconnection (automatically or manually) may be taken into account when determining the maximum demand. In other words if there is some system in place that reduces the load or cuts it off at a certain level then this can be allowed for when calculating maximum demand.
722.312.2.1: A circuit supplying charging equipment shall not include a PEN (combined neutral and earth) conductor.
722.41 Protection against electric shock…
The protective measures of obstacles and placing out of reach (Section 417) shall not be used as well as the extremely rare protective measures of non-conducting location (Regulation 418.1) and earth-free local equipotential bonding (Regulation 418.2) shall not be used.
722.411.4.1: Re TN Systems and electric shock protection…
If the charging point is outdoors or is likely to be used to charge a vehicle that is outdoors a PME (TN-C-S) earthing facility shall not be used as the means of earthing for the protective conductor of a charging point unless one of the following methods are used…
i) The charging point is part of a 3-phase installation that also supplies other types of loads and the maximum voltage between the main earthing terminal of the installation and Earth in the event of an open circuit on the PEN supply conductor does not exceed 70 V rms. (See Annex 722, item A722.2 for further information and also Regulation 641.5)
- Regulation 641.5: Any addition or alteration to an existing installation should not impair the installation safety and complies with current regulations
ii) The main earthing terminal of the installation is connected to an earth electrode complying with Regulation 544.1.1 (Size of main protective bonding conductor in relation to main Earth conductor size). The resistance between the main earthing terminal and Earth in the event of an open circuit on the PEN supply conductor does not exceed 70 V rms.(See Annex 722, item A722.3 for further information on this)
iii) Using a device that electrically disconnects the vehicle from the live supply conductors and protective earth in accordance with Regulation 543.3.3.101(ii) within 5 seconds if there is an open circuit fault on the PEN supply conductor and the voltage between the main earthing terminal of the installation and Earth exceeds 70 V rms. However, if the voltage exceeds 70 V rms for less than 4 seconds the device need not operate. The device should also provide isolation in accordance with Table 537.4. and the closing / resetting of the device shall only be possible if the voltage between the main earthing terminal of the installation and Earth does not exceed 70 V rms. (See Annex 722, item A722.4 for further information on this)
iv) In a single-phase installation protection is provided by a device that electrically disconnects the vehicle from the live supply conductors and protective earth in accordance with Regulation 543.3.3.101(ii) within 5 seconds if the voltage at the charging point between the line and neutral conductor is greater than 253 V rms or less than 207 V rms. The device should also provide isolation in accordance with Table 537.4. and the closing / resetting of the device shall only be possible if the voltage between the line and the neutral conductor is in the range of 207 to 253 V rms.
v) Protection is provided by the use of an alternative device to those in ‘iii’ and ‘iv’. The device shall disconnect the vehicle from the live conductors and the protective earth of the supply in accordance with Regulation 543.3.3.101(ii) and also provide isolation in accordance with Table 537.4.
- Regulation 543.3.3.101 No switching device shall be inserted in a protective conductor except (ii) a multipole, linked switching in which the protective conductor circuit is not interrupted before the live conductors and is re-established not later than when the live conductors are reconnected.
- Table 537.4 Guidance on the selection of protective, isolation and switching devices.
For more information please visit…